Field of the Invention
The present invention relates to a transmission comprising a synchronizer capable of connecting together a hub which is connected to a rotary shaft, and a dog gear relatively unrotatably spline-connected to a transmission gear which is relatively rotatably supported on the rotary shaft, wherein the synchronizer includes a sleeve spline-connected to the hub so as to be relatively unrotatable, and slidable in an axial direction, and a blocking ring disposed between the hub and the dog gear, and enabling the hub and the dog gear to frictionally engage with each other in response to movement of the sleeve.
Description of the Related Art
Japanese Patent Application Laid-open No. 2012-57786 has made publicly known a transmission including a double cone-type synchronizer which connects a rotary shaft of the transmission and a transmission gear supported on the rotary shaft so as to be relatively rotatable, the synchronizer including a blocking ring formed of three members, namely, an outer ring, an inner ring and an intermediate ring. Friction members provided to an inner peripheral surface of the outer ring are brought into contact with an outer peripheral surface of the intermediate ring, while friction members provided to an outer peripheral surface of the inner ring are brought into contact with an inner peripheral surface of the intermediate ring, thereby producing synchronous torque for synchronizing rotation of the rotary shaft and rotation of the transmission gear with each other.
In some of the above-mentioned double cone-type synchronizers, a dog gear is spline-connected to the transmission gear, and a sleeve supported by a hub is slid in an axial direction and engaged with dog teeth of the outer ring and dog teeth of the dog gear. However, if the engagement is not smoothly made, the dog gear, as pressed by the sleeve, may lean with a part of the dog gear spline-connected to the transmission gear as a fulcrum so that the inner ring may be damaged by being strongly squeezed between the dog gear and the hub.